There is nothing wrong with misgendering yourself, even if you’re out. You’ve been going by a different name and thought you were of a different gender for years! It takes some time to completely get used to it, and it’s nothing to be ashamed about.
Also, there’s nothing wrong with responding to people who misgender and dead name you without really realizing they misgendered you or deadnamed you. You grew up with those pronouns and that name and it’s just a habit to respond to them.
It doesn’t mean you ‘aren’t really trans’ or ‘don’t care if you get misgendered’. It simply means you are used to being called certain things and your brain responds to them out of habit.
^^^^